Implantable prostheses are commonly used to replace or augment body tissue. In the case of breast cancer, it is sometimes necessary to remove some or all of the mammary gland and surrounding tissue, which creates a void that can be filled with an implantable prosthesis. The implant serves to support surrounding tissue and to maintain the appearance of the body. The restoration of the normal appearance of the body has an extremely beneficial psychological effect on post-operative patients, eliminating much of the shock and depression that often follows extensive surgical procedures. Implantable prostheses are also used more generally for restoring the normal appearance of soft tissue in various areas of the body, such as the buttocks, chin, calf, etc.
Soft implantable prostheses typically include a relatively thin and flexible envelope or shell made of vulcanized (cured) silicone elastomer. The shell is filled either with a silicone gel or with a normal saline solution. The filling of the shell takes place before or after the shell is inserted through an incision in the patient.
In the United States, women can choose between two different types of breast implant shell surfaces: a smooth surface and a textured surface. The surgeon generally recommends the type of surface based on his or her technique and the shape of the breast implant chosen to best fit the needs of each patient.
Breast implants are not without complications, one of which is termed capsular contracture. This is a complication that occurs upon contraction of a fibrous outer capsule that forms around the implant, which tends to render the implant spherical and stiff and aesthetically undesirable. According to the United States Food and Drug Administration's (FDA) Breast Implant Consumer Handbook (2004), the literature shows that textured surface breast implants may decrease the capsular contracture rate.
Texturing may be provided in a number of ways. Silicone gel breast implants covered with a thin layer of textured polyurethane foam enjoyed considerable popularity in the 1980s because of their remarkable resistance to the early development of fibrous capsular contracture. For example, U.S. Pat. No. 3,293,663 describes a soft gel-filled prosthesis with a porous polyester fabric on the back side for tissue ingrowth and anchoring to the chest wall. Although these devices are no longer available in the U.S. because of regulatory constraint, their medical and commercial success stimulated interest in surface texturization of silicone implants.
Despite many advances in the development of safe and comfortable prosthetic implants, there remains room for improvement.